tests/CryptfsScryptHidlizationEquivalence_test.cpp - SHIFTPHONES/android_system_vold - Gitiles

 /*
 **
 ** Copyright 2017, The Android Open Source Project
 **
 ** Licensed under the Apache License, Version 2.0 (the "License");
 ** you may not use this file except in compliance with the License.
 ** You may obtain a copy of the License at
 **
 **     http://www.apache.org/licenses/LICENSE-2.0
 **
 ** Unless required by applicable law or agreed to in writing, software
 ** distributed under the License is distributed on an "AS IS" BASIS,
 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 ** See the License for the specific language governing permissions and
 ** limitations under the License.
 */

 #define LOG_TAG "scrypt_test"
 #include <log/log.h>

 #include <hardware/keymaster0.h>
 #include <hardware/keymaster1.h>
 #include <cstring>
 #include <gtest/gtest.h>

 #include "../cryptfs.h"
 #include "../Keymaster.h"

 #ifdef CONFIG_HW_DISK_ENCRYPTION
 #include "cryptfs_hw.h"
 #endif

 #define min(a, b) ((a) < (b) ? (a) : (b))

 /* Maximum allowed keymaster blob size. */
 #define KEYMASTER_BLOB_SIZE 2048

 /* Key Derivation Function algorithms */
 #define KDF_PBKDF2 1
 #define KDF_SCRYPT 2
 /* Algorithms 3 & 4 deprecated before shipping outside of google, so removed */
 #define KDF_SCRYPT_KEYMASTER 5

 #define KEY_LEN_BYTES 16

 #define DEFAULT_PASSWORD "default_password"

 #define RSA_KEY_SIZE 2048
 #define RSA_KEY_SIZE_BYTES (RSA_KEY_SIZE / 8)
 #define RSA_EXPONENT 0x10001
 #define KEYMASTER_CRYPTFS_RATE_LIMIT 1  // Maximum one try per second

 static int keymaster_init(keymaster0_device_t **keymaster0_dev,
                           keymaster1_device_t **keymaster1_dev)
 {
     int rc;

     const hw_module_t* mod;
     rc = hw_get_module_by_class(KEYSTORE_HARDWARE_MODULE_ID, NULL, &mod);
     if (rc) {
         ALOGE("could not find any keystore module");
         goto err;
     }

     SLOGI("keymaster module name is %s", mod->name);
     SLOGI("keymaster version is %d", mod->module_api_version);

     *keymaster0_dev = NULL;
     *keymaster1_dev = NULL;
     if (mod->module_api_version == KEYMASTER_MODULE_API_VERSION_1_0) {
         SLOGI("Found keymaster1 module, using keymaster1 API.");
         rc = keymaster1_open(mod, keymaster1_dev);
     } else {
         SLOGI("Found keymaster0 module, using keymaster0 API.");
         rc = keymaster0_open(mod, keymaster0_dev);
     }

     if (rc) {
         ALOGE("could not open keymaster device in %s (%s)",
               KEYSTORE_HARDWARE_MODULE_ID, strerror(-rc));
         goto err;
     }

     return 0;

 err:
     *keymaster0_dev = NULL;
     *keymaster1_dev = NULL;
     return rc;
 }

 /* Should we use keymaster? */
 static int keymaster_check_compatibility_old()
 {
     keymaster0_device_t *keymaster0_dev = 0;
     keymaster1_device_t *keymaster1_dev = 0;
     int rc = 0;

     if (keymaster_init(&keymaster0_dev, &keymaster1_dev)) {
         SLOGE("Failed to init keymaster");
         rc = -1;
         goto out;
     }

     if (keymaster1_dev) {
         rc = 1;
         goto out;
     }

     if (!keymaster0_dev || !keymaster0_dev->common.module) {
         rc = -1;
         goto out;
     }

     // TODO(swillden): Check to see if there's any reason to require v0.3.  I think v0.1 and v0.2
     // should work.
     if (keymaster0_dev->common.module->module_api_version
             < KEYMASTER_MODULE_API_VERSION_0_3) {
         rc = 0;
         goto out;
     }

     if (!(keymaster0_dev->flags & KEYMASTER_SOFTWARE_ONLY) &&
         (keymaster0_dev->flags & KEYMASTER_BLOBS_ARE_STANDALONE)) {
         rc = 1;
     }

 out:
     if (keymaster1_dev) {
         keymaster1_close(keymaster1_dev);
     }
     if (keymaster0_dev) {
         keymaster0_close(keymaster0_dev);
     }
     return rc;
 }

 /* Create a new keymaster key and store it in this footer */
 static int keymaster_create_key_old(struct crypt_mnt_ftr *ftr)
 {
     uint8_t* key = 0;
     keymaster0_device_t *keymaster0_dev = 0;
     keymaster1_device_t *keymaster1_dev = 0;

     if (ftr->keymaster_blob_size) {
         SLOGI("Already have key");
         return 0;
     }

     if (keymaster_init(&keymaster0_dev, &keymaster1_dev)) {
         SLOGE("Failed to init keymaster");
         return -1;
     }

     int rc = 0;
     size_t key_size = 0;
     if (keymaster1_dev) {
         keymaster_key_param_t params[] = {
             /* Algorithm & size specifications.  Stick with RSA for now.  Switch to AES later. */
             keymaster_param_enum(KM_TAG_ALGORITHM, KM_ALGORITHM_RSA),
             keymaster_param_int(KM_TAG_KEY_SIZE, RSA_KEY_SIZE),
             keymaster_param_long(KM_TAG_RSA_PUBLIC_EXPONENT, RSA_EXPONENT),

             /* The only allowed purpose for this key is signing. */
             keymaster_param_enum(KM_TAG_PURPOSE, KM_PURPOSE_SIGN),

             /* Padding & digest specifications. */
             keymaster_param_enum(KM_TAG_PADDING, KM_PAD_NONE),
             keymaster_param_enum(KM_TAG_DIGEST, KM_DIGEST_NONE),

             /* Require that the key be usable in standalone mode.  File system isn't available. */
             keymaster_param_enum(KM_TAG_BLOB_USAGE_REQUIREMENTS, KM_BLOB_STANDALONE),

             /* No auth requirements, because cryptfs is not yet integrated with gatekeeper. */
             keymaster_param_bool(KM_TAG_NO_AUTH_REQUIRED),

             /* Rate-limit key usage attempts, to rate-limit brute force */
             keymaster_param_int(KM_TAG_MIN_SECONDS_BETWEEN_OPS, KEYMASTER_CRYPTFS_RATE_LIMIT),
         };
         keymaster_key_param_set_t param_set = { params, sizeof(params)/sizeof(*params) };
         keymaster_key_blob_t key_blob;
         keymaster_error_t error = keymaster1_dev->generate_key(keymaster1_dev, &param_set,
                                                                &key_blob,
                                                                NULL /* characteristics */);
         if (error != KM_ERROR_OK) {
             SLOGE("Failed to generate keymaster1 key, error %d", error);
             rc = -1;
             goto out;
         }

         key = (uint8_t*)key_blob.key_material;
         key_size = key_blob.key_material_size;
     }
     else if (keymaster0_dev) {
         keymaster_rsa_keygen_params_t params;
         memset(&params, '\0', sizeof(params));
         params.public_exponent = RSA_EXPONENT;
         params.modulus_size = RSA_KEY_SIZE;

         if (keymaster0_dev->generate_keypair(keymaster0_dev, TYPE_RSA, &params,
                                              &key, &key_size)) {
             SLOGE("Failed to generate keypair");
             rc = -1;
             goto out;
         }
     } else {
         SLOGE("Cryptfs bug: keymaster_init succeeded but didn't initialize a device");
         rc = -1;
         goto out;
     }

     if (key_size > KEYMASTER_BLOB_SIZE) {
         SLOGE("Keymaster key too large for crypto footer");
         rc = -1;
         goto out;
     }

     memcpy(ftr->keymaster_blob, key, key_size);
     ftr->keymaster_blob_size = key_size;

 out:
     if (keymaster0_dev)
         keymaster0_close(keymaster0_dev);
     if (keymaster1_dev)
         keymaster1_close(keymaster1_dev);
     free(key);
     return rc;
 }

 /* This signs the given object using the keymaster key. */
 static int keymaster_sign_object_old(struct crypt_mnt_ftr *ftr,
                                  const unsigned char *object,
                                  const size_t object_size,
                                  unsigned char **signature,
                                  size_t *signature_size)
 {
     int rc = 0;
     keymaster0_device_t *keymaster0_dev = 0;
     keymaster1_device_t *keymaster1_dev = 0;

     unsigned char to_sign[RSA_KEY_SIZE_BYTES];
     size_t to_sign_size = sizeof(to_sign);
     memset(to_sign, 0, RSA_KEY_SIZE_BYTES);

     if (keymaster_init(&keymaster0_dev, &keymaster1_dev)) {
         SLOGE("Failed to init keymaster");
         rc = -1;
         goto out;
     }

     // To sign a message with RSA, the message must satisfy two
     // constraints:
     //
     // 1. The message, when interpreted as a big-endian numeric value, must
     //    be strictly less than the public modulus of the RSA key.  Note
     //    that because the most significant bit of the public modulus is
     //    guaranteed to be 1 (else it's an (n-1)-bit key, not an n-bit
     //    key), an n-bit message with most significant bit 0 always
     //    satisfies this requirement.
     //
     // 2. The message must have the same length in bits as the public
     //    modulus of the RSA key.  This requirement isn't mathematically
     //    necessary, but is necessary to ensure consistency in
     //    implementations.
     switch (ftr->kdf_type) {
         case KDF_SCRYPT_KEYMASTER:
             // This ensures the most significant byte of the signed message
             // is zero.  We could have zero-padded to the left instead, but
             // this approach is slightly more robust against changes in
             // object size.  However, it's still broken (but not unusably
             // so) because we really should be using a proper deterministic
             // RSA padding function, such as PKCS1.
             memcpy(to_sign + 1, object, min(RSA_KEY_SIZE_BYTES - 1, object_size));
             SLOGI("Signing safely-padded object");
             break;
         default:
             SLOGE("Unknown KDF type %d", ftr->kdf_type);
             rc = -1;
             goto out;
     }

     if (keymaster0_dev) {
         keymaster_rsa_sign_params_t params;
         params.digest_type = DIGEST_NONE;
         params.padding_type = PADDING_NONE;

         rc = keymaster0_dev->sign_data(keymaster0_dev,
                                       &params,
                                       ftr->keymaster_blob,
                                       ftr->keymaster_blob_size,
                                       to_sign,
                                       to_sign_size,
                                       signature,
                                       signature_size);
         goto out;
     } else if (keymaster1_dev) {
         keymaster_key_blob_t key = { ftr->keymaster_blob, ftr->keymaster_blob_size };
         keymaster_key_param_t params[] = {
             keymaster_param_enum(KM_TAG_PADDING, KM_PAD_NONE),
             keymaster_param_enum(KM_TAG_DIGEST, KM_DIGEST_NONE),
         };
         keymaster_key_param_set_t param_set = { params, sizeof(params)/sizeof(*params) };
         keymaster_operation_handle_t op_handle;
         keymaster_error_t error = keymaster1_dev->begin(keymaster1_dev, KM_PURPOSE_SIGN, &key,
                                                         &param_set, NULL /* out_params */,
                                                         &op_handle);
         if (error == KM_ERROR_KEY_RATE_LIMIT_EXCEEDED) {
             // Key usage has been rate-limited.  Wait a bit and try again.
             sleep(KEYMASTER_CRYPTFS_RATE_LIMIT);
             error = keymaster1_dev->begin(keymaster1_dev, KM_PURPOSE_SIGN, &key,
                                           &param_set, NULL /* out_params */,
                                           &op_handle);
         }
         if (error != KM_ERROR_OK) {
             SLOGE("Error starting keymaster signature transaction: %d", error);
             rc = -1;
             goto out;
         }

         keymaster_blob_t input = { to_sign, to_sign_size };
         size_t input_consumed;
         error = keymaster1_dev->update(keymaster1_dev, op_handle, NULL /* in_params */,
                                        &input, &input_consumed, NULL /* out_params */,
                                        NULL /* output */);
         if (error != KM_ERROR_OK) {
             SLOGE("Error sending data to keymaster signature transaction: %d", error);
             rc = -1;
             goto out;
         }
         if (input_consumed != to_sign_size) {
             // This should never happen.  If it does, it's a bug in the keymaster implementation.
             SLOGE("Keymaster update() did not consume all data.");
             keymaster1_dev->abort(keymaster1_dev, op_handle);
             rc = -1;
             goto out;
         }

         keymaster_blob_t tmp_sig;
         error = keymaster1_dev->finish(keymaster1_dev, op_handle, NULL /* in_params */,
                                        NULL /* verify signature */, NULL /* out_params */,
                                        &tmp_sig);
         if (error != KM_ERROR_OK) {
             SLOGE("Error finishing keymaster signature transaction: %d", error);
             rc = -1;
             goto out;
         }

         *signature = (uint8_t*)tmp_sig.data;
         *signature_size = tmp_sig.data_length;
     } else {
         SLOGE("Cryptfs bug: keymaster_init succeded but didn't initialize a device.");
         rc = -1;
         goto out;
     }

     out:
         if (keymaster1_dev)
             keymaster1_close(keymaster1_dev);
         if (keymaster0_dev)
             keymaster0_close(keymaster0_dev);

         return rc;
 }


 /* Should we use keymaster? */
 static int keymaster_check_compatibility_new()
 {
     return keymaster_compatibility_cryptfs_scrypt();
 }

 #if 0
 /* Create a new keymaster key and store it in this footer */
 static int keymaster_create_key_new(struct crypt_mnt_ftr *ftr)
 {
     if (ftr->keymaster_blob_size) {
         SLOGI("Already have key");
         return 0;
     }

     int rc = keymaster_create_key_for_cryptfs_scrypt(RSA_KEY_SIZE, RSA_EXPONENT,
             KEYMASTER_CRYPTFS_RATE_LIMIT, ftr->keymaster_blob, KEYMASTER_BLOB_SIZE,
             &ftr->keymaster_blob_size);
     if (rc) {
         if (ftr->keymaster_blob_size > KEYMASTER_BLOB_SIZE) {
             SLOGE("Keymaster key blob to large)");
             ftr->keymaster_blob_size = 0;
         }
         SLOGE("Failed to generate keypair");
         return -1;
     }
     return 0;
 }
 #endif

 /* This signs the given object using the keymaster key. */
 static int keymaster_sign_object_new(struct crypt_mnt_ftr *ftr,
                                  const unsigned char *object,
                                  const size_t object_size,
                                  unsigned char **signature,
                                  size_t *signature_size)
 {
     unsigned char to_sign[RSA_KEY_SIZE_BYTES];
     size_t to_sign_size = sizeof(to_sign);
     memset(to_sign, 0, RSA_KEY_SIZE_BYTES);

     // To sign a message with RSA, the message must satisfy two
     // constraints:
     //
     // 1. The message, when interpreted as a big-endian numeric value, must
     //    be strictly less than the public modulus of the RSA key.  Note
     //    that because the most significant bit of the public modulus is
     //    guaranteed to be 1 (else it's an (n-1)-bit key, not an n-bit
     //    key), an n-bit message with most significant bit 0 always
     //    satisfies this requirement.
     //
     // 2. The message must have the same length in bits as the public
     //    modulus of the RSA key.  This requirement isn't mathematically
     //    necessary, but is necessary to ensure consistency in
     //    implementations.
     switch (ftr->kdf_type) {
         case KDF_SCRYPT_KEYMASTER:
             // This ensures the most significant byte of the signed message
             // is zero.  We could have zero-padded to the left instead, but
             // this approach is slightly more robust against changes in
             // object size.  However, it's still broken (but not unusably
             // so) because we really should be using a proper deterministic
             // RSA padding function, such as PKCS1.
             memcpy(to_sign + 1, object, min(RSA_KEY_SIZE_BYTES - 1, object_size));
             SLOGI("Signing safely-padded object");
             break;
         default:
             SLOGE("Unknown KDF type %d", ftr->kdf_type);
             return -1;
     }
     if (keymaster_sign_object_for_cryptfs_scrypt(
             ftr->keymaster_blob, ftr->keymaster_blob_size, KEYMASTER_CRYPTFS_RATE_LIMIT, to_sign,
             to_sign_size, signature, signature_size) != KeymasterSignResult::ok)
         return -1;
     return 0;
 }

 namespace android {

 class CryptFsTest : public testing::Test {
 protected:
     virtual void SetUp() {
     }

     virtual void TearDown() {
     }
 };

 TEST_F(CryptFsTest, ScryptHidlizationEquivalenceTest) {
     crypt_mnt_ftr ftr;
     ftr.kdf_type = KDF_SCRYPT_KEYMASTER;
     ftr.keymaster_blob_size = 0;

     ASSERT_EQ(0, keymaster_create_key_old(&ftr));

     uint8_t *sig1 = nullptr;
     uint8_t *sig2 = nullptr;
     size_t sig_size1 = 123456789;
     size_t sig_size2 = 123456789;
     uint8_t object[] = "the object";

     ASSERT_EQ(1, keymaster_check_compatibility_old());
     ASSERT_EQ(1, keymaster_check_compatibility_new());
     ASSERT_EQ(0, keymaster_sign_object_old(&ftr, object, 10, &sig1, &sig_size1));
     ASSERT_EQ(0, keymaster_sign_object_new(&ftr, object, 10, &sig2, &sig_size2));

     ASSERT_EQ(sig_size1, sig_size2);
     ASSERT_NE(nullptr, sig1);
     ASSERT_NE(nullptr, sig2);
     EXPECT_EQ(0, memcmp(sig1, sig2, sig_size1));
     free(sig1);
     free(sig2);
 }

 }
	/*
	**
	** Copyright 2017, The Android Open Source Project
	**
	** Licensed under the Apache License, Version 2.0 (the "License");
	** you may not use this file except in compliance with the License.
	** You may obtain a copy of the License at
	**
	** http://www.apache.org/licenses/LICENSE-2.0
	**
	** Unless required by applicable law or agreed to in writing, software
	** distributed under the License is distributed on an "AS IS" BASIS,
	** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	** See the License for the specific language governing permissions and
	** limitations under the License.
	*/

	#define LOG_TAG "scrypt_test"
	#include <log/log.h>

	#include <hardware/keymaster0.h>
	#include <hardware/keymaster1.h>
	#include <cstring>
	#include <gtest/gtest.h>

	#include "../cryptfs.h"
	#include "../Keymaster.h"

	#ifdef CONFIG_HW_DISK_ENCRYPTION
	#include "cryptfs_hw.h"
	#endif

	#define min(a, b) ((a) < (b) ? (a) : (b))

	/* Maximum allowed keymaster blob size. */
	#define KEYMASTER_BLOB_SIZE 2048

	/* Key Derivation Function algorithms */
	#define KDF_PBKDF2 1
	#define KDF_SCRYPT 2
	/* Algorithms 3 & 4 deprecated before shipping outside of google, so removed */
	#define KDF_SCRYPT_KEYMASTER 5

	#define KEY_LEN_BYTES 16

	#define DEFAULT_PASSWORD "default_password"

	#define RSA_KEY_SIZE 2048
	#define RSA_KEY_SIZE_BYTES (RSA_KEY_SIZE / 8)
	#define RSA_EXPONENT 0x10001
	#define KEYMASTER_CRYPTFS_RATE_LIMIT 1 // Maximum one try per second

	static int keymaster_init(keymaster0_device_t **keymaster0_dev,
	keymaster1_device_t **keymaster1_dev)
	{
	int rc;

	const hw_module_t* mod;
	rc = hw_get_module_by_class(KEYSTORE_HARDWARE_MODULE_ID, NULL, &mod);
	if (rc) {
	ALOGE("could not find any keystore module");
	goto err;
	}

	SLOGI("keymaster module name is %s", mod->name);
	SLOGI("keymaster version is %d", mod->module_api_version);

	*keymaster0_dev = NULL;
	*keymaster1_dev = NULL;
	if (mod->module_api_version == KEYMASTER_MODULE_API_VERSION_1_0) {
	SLOGI("Found keymaster1 module, using keymaster1 API.");
	rc = keymaster1_open(mod, keymaster1_dev);
	} else {
	SLOGI("Found keymaster0 module, using keymaster0 API.");
	rc = keymaster0_open(mod, keymaster0_dev);
	}

	if (rc) {
	ALOGE("could not open keymaster device in %s (%s)",
	KEYSTORE_HARDWARE_MODULE_ID, strerror(-rc));
	goto err;
	}

	return 0;

	err:
	*keymaster0_dev = NULL;
	*keymaster1_dev = NULL;
	return rc;
	}

	/* Should we use keymaster? */
	static int keymaster_check_compatibility_old()
	{
	keymaster0_device_t *keymaster0_dev = 0;
	keymaster1_device_t *keymaster1_dev = 0;
	int rc = 0;

	if (keymaster_init(&keymaster0_dev, &keymaster1_dev)) {
	SLOGE("Failed to init keymaster");
	rc = -1;
	goto out;
	}

	if (keymaster1_dev) {
	rc = 1;
	goto out;
	}

	if (!keymaster0_dev \|\| !keymaster0_dev->common.module) {
	rc = -1;
	goto out;
	}

	// TODO(swillden): Check to see if there's any reason to require v0.3. I think v0.1 and v0.2
	// should work.
	if (keymaster0_dev->common.module->module_api_version
	< KEYMASTER_MODULE_API_VERSION_0_3) {
	rc = 0;
	goto out;
	}

	if (!(keymaster0_dev->flags & KEYMASTER_SOFTWARE_ONLY) &&
	(keymaster0_dev->flags & KEYMASTER_BLOBS_ARE_STANDALONE)) {
	rc = 1;
	}

	out:
	if (keymaster1_dev) {
	keymaster1_close(keymaster1_dev);
	}
	if (keymaster0_dev) {
	keymaster0_close(keymaster0_dev);
	}
	return rc;
	}

	/* Create a new keymaster key and store it in this footer */
	static int keymaster_create_key_old(struct crypt_mnt_ftr *ftr)
	{
	uint8_t* key = 0;
	keymaster0_device_t *keymaster0_dev = 0;
	keymaster1_device_t *keymaster1_dev = 0;

	if (ftr->keymaster_blob_size) {
	SLOGI("Already have key");
	return 0;
	}

	if (keymaster_init(&keymaster0_dev, &keymaster1_dev)) {
	SLOGE("Failed to init keymaster");
	return -1;
	}

	int rc = 0;
	size_t key_size = 0;
	if (keymaster1_dev) {
	keymaster_key_param_t params[] = {
	/* Algorithm & size specifications. Stick with RSA for now. Switch to AES later. */
	keymaster_param_enum(KM_TAG_ALGORITHM, KM_ALGORITHM_RSA),
	keymaster_param_int(KM_TAG_KEY_SIZE, RSA_KEY_SIZE),
	keymaster_param_long(KM_TAG_RSA_PUBLIC_EXPONENT, RSA_EXPONENT),

	/* The only allowed purpose for this key is signing. */
	keymaster_param_enum(KM_TAG_PURPOSE, KM_PURPOSE_SIGN),

	/* Padding & digest specifications. */
	keymaster_param_enum(KM_TAG_PADDING, KM_PAD_NONE),
	keymaster_param_enum(KM_TAG_DIGEST, KM_DIGEST_NONE),

	/* Require that the key be usable in standalone mode. File system isn't available. */
	keymaster_param_enum(KM_TAG_BLOB_USAGE_REQUIREMENTS, KM_BLOB_STANDALONE),

	/* No auth requirements, because cryptfs is not yet integrated with gatekeeper. */
	keymaster_param_bool(KM_TAG_NO_AUTH_REQUIRED),

	/* Rate-limit key usage attempts, to rate-limit brute force */
	keymaster_param_int(KM_TAG_MIN_SECONDS_BETWEEN_OPS, KEYMASTER_CRYPTFS_RATE_LIMIT),
	};
	keymaster_key_param_set_t param_set = { params, sizeof(params)/sizeof(*params) };
	keymaster_key_blob_t key_blob;
	keymaster_error_t error = keymaster1_dev->generate_key(keymaster1_dev, &param_set,
	&key_blob,
	NULL /* characteristics */);
	if (error != KM_ERROR_OK) {
	SLOGE("Failed to generate keymaster1 key, error %d", error);
	rc = -1;
	goto out;
	}

	key = (uint8_t*)key_blob.key_material;
	key_size = key_blob.key_material_size;
	}
	else if (keymaster0_dev) {
	keymaster_rsa_keygen_params_t params;
	memset(&params, '\0', sizeof(params));
	params.public_exponent = RSA_EXPONENT;
	params.modulus_size = RSA_KEY_SIZE;

	if (keymaster0_dev->generate_keypair(keymaster0_dev, TYPE_RSA, &params,
	&key, &key_size)) {
	SLOGE("Failed to generate keypair");
	rc = -1;
	goto out;
	}
	} else {
	SLOGE("Cryptfs bug: keymaster_init succeeded but didn't initialize a device");
	rc = -1;
	goto out;
	}

	if (key_size > KEYMASTER_BLOB_SIZE) {
	SLOGE("Keymaster key too large for crypto footer");
	rc = -1;
	goto out;
	}

	memcpy(ftr->keymaster_blob, key, key_size);
	ftr->keymaster_blob_size = key_size;

	out:
	if (keymaster0_dev)
	keymaster0_close(keymaster0_dev);
	if (keymaster1_dev)
	keymaster1_close(keymaster1_dev);
	free(key);
	return rc;
	}

	/* This signs the given object using the keymaster key. */
	static int keymaster_sign_object_old(struct crypt_mnt_ftr *ftr,
	const unsigned char *object,
	const size_t object_size,
	unsigned char **signature,
	size_t *signature_size)
	{
	int rc = 0;
	keymaster0_device_t *keymaster0_dev = 0;
	keymaster1_device_t *keymaster1_dev = 0;

	unsigned char to_sign[RSA_KEY_SIZE_BYTES];
	size_t to_sign_size = sizeof(to_sign);
	memset(to_sign, 0, RSA_KEY_SIZE_BYTES);

	if (keymaster_init(&keymaster0_dev, &keymaster1_dev)) {
	SLOGE("Failed to init keymaster");
	rc = -1;
	goto out;
	}

	// To sign a message with RSA, the message must satisfy two
	// constraints:
	//
	// 1. The message, when interpreted as a big-endian numeric value, must
	// be strictly less than the public modulus of the RSA key. Note
	// that because the most significant bit of the public modulus is
	// guaranteed to be 1 (else it's an (n-1)-bit key, not an n-bit
	// key), an n-bit message with most significant bit 0 always
	// satisfies this requirement.
	//
	// 2. The message must have the same length in bits as the public
	// modulus of the RSA key. This requirement isn't mathematically
	// necessary, but is necessary to ensure consistency in
	// implementations.
	switch (ftr->kdf_type) {
	case KDF_SCRYPT_KEYMASTER:
	// This ensures the most significant byte of the signed message
	// is zero. We could have zero-padded to the left instead, but
	// this approach is slightly more robust against changes in
	// object size. However, it's still broken (but not unusably
	// so) because we really should be using a proper deterministic
	// RSA padding function, such as PKCS1.
	memcpy(to_sign + 1, object, min(RSA_KEY_SIZE_BYTES - 1, object_size));
	SLOGI("Signing safely-padded object");
	break;
	default:
	SLOGE("Unknown KDF type %d", ftr->kdf_type);
	rc = -1;
	goto out;
	}

	if (keymaster0_dev) {
	keymaster_rsa_sign_params_t params;
	params.digest_type = DIGEST_NONE;
	params.padding_type = PADDING_NONE;

	rc = keymaster0_dev->sign_data(keymaster0_dev,
	&params,
	ftr->keymaster_blob,
	ftr->keymaster_blob_size,
	to_sign,
	to_sign_size,
	signature,
	signature_size);
	goto out;
	} else if (keymaster1_dev) {
	keymaster_key_blob_t key = { ftr->keymaster_blob, ftr->keymaster_blob_size };
	keymaster_key_param_t params[] = {
	keymaster_param_enum(KM_TAG_PADDING, KM_PAD_NONE),
	keymaster_param_enum(KM_TAG_DIGEST, KM_DIGEST_NONE),
	};
	keymaster_key_param_set_t param_set = { params, sizeof(params)/sizeof(*params) };
	keymaster_operation_handle_t op_handle;
	keymaster_error_t error = keymaster1_dev->begin(keymaster1_dev, KM_PURPOSE_SIGN, &key,
	&param_set, NULL /* out_params */,
	&op_handle);
	if (error == KM_ERROR_KEY_RATE_LIMIT_EXCEEDED) {
	// Key usage has been rate-limited. Wait a bit and try again.
	sleep(KEYMASTER_CRYPTFS_RATE_LIMIT);
	error = keymaster1_dev->begin(keymaster1_dev, KM_PURPOSE_SIGN, &key,
	&param_set, NULL /* out_params */,
	&op_handle);
	}
	if (error != KM_ERROR_OK) {
	SLOGE("Error starting keymaster signature transaction: %d", error);
	rc = -1;
	goto out;
	}

	keymaster_blob_t input = { to_sign, to_sign_size };
	size_t input_consumed;
	error = keymaster1_dev->update(keymaster1_dev, op_handle, NULL /* in_params */,
	&input, &input_consumed, NULL /* out_params */,
	NULL /* output */);
	if (error != KM_ERROR_OK) {
	SLOGE("Error sending data to keymaster signature transaction: %d", error);
	rc = -1;
	goto out;
	}
	if (input_consumed != to_sign_size) {
	// This should never happen. If it does, it's a bug in the keymaster implementation.
	SLOGE("Keymaster update() did not consume all data.");
	keymaster1_dev->abort(keymaster1_dev, op_handle);
	rc = -1;
	goto out;
	}

	keymaster_blob_t tmp_sig;
	error = keymaster1_dev->finish(keymaster1_dev, op_handle, NULL /* in_params */,
	NULL /* verify signature /, NULL / out_params */,
	&tmp_sig);
	if (error != KM_ERROR_OK) {
	SLOGE("Error finishing keymaster signature transaction: %d", error);
	rc = -1;
	goto out;
	}

	signature = (uint8_t)tmp_sig.data;
	*signature_size = tmp_sig.data_length;
	} else {
	SLOGE("Cryptfs bug: keymaster_init succeded but didn't initialize a device.");
	rc = -1;
	goto out;
	}

	out:
	if (keymaster1_dev)
	keymaster1_close(keymaster1_dev);
	if (keymaster0_dev)
	keymaster0_close(keymaster0_dev);

	return rc;
	}


	/* Should we use keymaster? */
	static int keymaster_check_compatibility_new()
	{
	return keymaster_compatibility_cryptfs_scrypt();
	}

	#if 0
	/* Create a new keymaster key and store it in this footer */
	static int keymaster_create_key_new(struct crypt_mnt_ftr *ftr)
	{
	if (ftr->keymaster_blob_size) {
	SLOGI("Already have key");
	return 0;
	}

	int rc = keymaster_create_key_for_cryptfs_scrypt(RSA_KEY_SIZE, RSA_EXPONENT,
	KEYMASTER_CRYPTFS_RATE_LIMIT, ftr->keymaster_blob, KEYMASTER_BLOB_SIZE,
	&ftr->keymaster_blob_size);
	if (rc) {
	if (ftr->keymaster_blob_size > KEYMASTER_BLOB_SIZE) {
	SLOGE("Keymaster key blob to large)");
	ftr->keymaster_blob_size = 0;
	}
	SLOGE("Failed to generate keypair");
	return -1;
	}
	return 0;
	}
	#endif

	/* This signs the given object using the keymaster key. */
	static int keymaster_sign_object_new(struct crypt_mnt_ftr *ftr,
	const unsigned char *object,
	const size_t object_size,
	unsigned char **signature,
	size_t *signature_size)
	{
	unsigned char to_sign[RSA_KEY_SIZE_BYTES];
	size_t to_sign_size = sizeof(to_sign);
	memset(to_sign, 0, RSA_KEY_SIZE_BYTES);

	// To sign a message with RSA, the message must satisfy two
	// constraints:
	//
	// 1. The message, when interpreted as a big-endian numeric value, must
	// be strictly less than the public modulus of the RSA key. Note
	// that because the most significant bit of the public modulus is
	// guaranteed to be 1 (else it's an (n-1)-bit key, not an n-bit
	// key), an n-bit message with most significant bit 0 always
	// satisfies this requirement.
	//
	// 2. The message must have the same length in bits as the public
	// modulus of the RSA key. This requirement isn't mathematically
	// necessary, but is necessary to ensure consistency in
	// implementations.
	switch (ftr->kdf_type) {
	case KDF_SCRYPT_KEYMASTER:
	// This ensures the most significant byte of the signed message
	// is zero. We could have zero-padded to the left instead, but
	// this approach is slightly more robust against changes in
	// object size. However, it's still broken (but not unusably
	// so) because we really should be using a proper deterministic
	// RSA padding function, such as PKCS1.
	memcpy(to_sign + 1, object, min(RSA_KEY_SIZE_BYTES - 1, object_size));
	SLOGI("Signing safely-padded object");
	break;
	default:
	SLOGE("Unknown KDF type %d", ftr->kdf_type);
	return -1;
	}
	if (keymaster_sign_object_for_cryptfs_scrypt(
	ftr->keymaster_blob, ftr->keymaster_blob_size, KEYMASTER_CRYPTFS_RATE_LIMIT, to_sign,
	to_sign_size, signature, signature_size) != KeymasterSignResult::ok)
	return -1;
	return 0;
	}

	namespace android {

	class CryptFsTest : public testing::Test {
	protected:
	virtual void SetUp() {
	}

	virtual void TearDown() {
	}
	};

	TEST_F(CryptFsTest, ScryptHidlizationEquivalenceTest) {
	crypt_mnt_ftr ftr;
	ftr.kdf_type = KDF_SCRYPT_KEYMASTER;
	ftr.keymaster_blob_size = 0;

	ASSERT_EQ(0, keymaster_create_key_old(&ftr));

	uint8_t *sig1 = nullptr;
	uint8_t *sig2 = nullptr;
	size_t sig_size1 = 123456789;
	size_t sig_size2 = 123456789;
	uint8_t object[] = "the object";

	ASSERT_EQ(1, keymaster_check_compatibility_old());
	ASSERT_EQ(1, keymaster_check_compatibility_new());
	ASSERT_EQ(0, keymaster_sign_object_old(&ftr, object, 10, &sig1, &sig_size1));
	ASSERT_EQ(0, keymaster_sign_object_new(&ftr, object, 10, &sig2, &sig_size2));

	ASSERT_EQ(sig_size1, sig_size2);
	ASSERT_NE(nullptr, sig1);
	ASSERT_NE(nullptr, sig2);
	EXPECT_EQ(0, memcmp(sig1, sig2, sig_size1));
	free(sig1);
	free(sig2);
	}

	}